Investigation of very high radiation hardness of 21 μm silicon self-biased detectors

The radiation damage of 21 μ m thick self-biased epitaxial Δ E detectors were tested as a function of fluence of 90 MeV 14 N ions. Technology of production and technique of measurements of Δ E detectors were described. A new technique of soldering contact to thin detector is shown. In the present work the 21 μ m thick self-biased detectors marked as d4 and d5 show proper operation with the fluence about 4 · 10 15 ions/cm 2 and the fluence about 8 · 10 15 ions/cm 2 , respectively. The charge collection efficiency of thin d5 Δ E detector was increased about double at fluence about 8 · 10 15 ions/cm 2 . The charge collection efficiency of thin d4 Δ E detector was increased about 35 % at fluence about 4 · 10 15 ions/cm 2 followed decrease about 70 % of detector counting rate registration from fluence 9.1 · 10 15 ions/cm 2 to fluence about 5 · 10 16 ions/cm 2 due to partially removing of Al evaporated contact from detector surface as an effect of heavy ion irradiation. Increase of charge collection efficiency of thin self-biased detectors manufactured by the low-temperature technique was probably produced by increasing of build-in potential as an effect of activate carrier concentration of boron ions in epitaxial layer by heavy ion irradiation.